Java J2EE Interview Question: Difference between Session and Entity Beans in Java EE

In Java EE, Session beans and Entity beans are two types of Enterprise JavaBeans (EJBs) that serve different purposes.

Session Beans

Session beans are used to perform business logic and act as intermediaries between clients and the database. They are not persistent and are typically short-lived. There are two types of session beans: stateful and stateless.

Stateful Session Beans

Stateful session beans maintain conversational state with a specific client across multiple method invocations.

Stateless Session Beans

Stateless session beans do not maintain conversational state and are pooled by the container to handle client requests.

Entity Beans

Entity beans represent persistent data stored in a database. They are used to map Java objects to database tables and provide a way to interact with the database through Java code.

The main differences between Session and Entity beans are:

• Session beans are used for business logic, while entity beans are used for data persistence.
• Session beans are typically short-lived, while entity beans represent persistent data.
• Session beans can be stateful or stateless, while entity beans are always stateless.

Understanding the difference between Session and Entity beans is important for developing scalable and maintainable Java EE applications.